Have a Goodman furnace, no AC. Made in 1991 Installed 1992. 80 % High eff. This thing is driving me nuts!! Starting last year every once in a while the burners would not light clear across, say only 3 out of five for the first few tries then they would all kick in and heat up the house as usual. THie season it came to the point the thing would shut down after several tries and not fire up at all. then maybe an hour later it would fire up fine. I have cleaned the jets, replaced the air induction blower, cleaned the gas tube, replaced the gas valve and checked the voltage to the solenoid an valve 24.7 volts. Darn thing just acts like there isn't enough gas pressure getting through the valve. THis is a propane setup and I have installed the LP spring. What am I missing!? I know the hard surface igniter is working right or the valve wouldn't be getting the 24 volt current. Yes I have propane! (heh heh ) 400 gallon tank at 65%
DAryl

Hello Daryl:
You may want to check the heat exchanger for leaks. Using LP gas seems to burn out the exchanger tubes more quickly than natrual gas would. It is about 16 years old now and 12 to 20 years is the normal economic life of a furnace.
Check the wiring diagram for a limit switch that detects the leaking exchanger.
Glenn

Figured it out!! Finally broke down and called the repairman. Found out the burners were rusted and not firing! Duh! Seems like I missed that one! Glenn , the heat exchanger was replaced about 6 years after furnace installation. The basement is quite humid during the spring -summer and fall due to stacked stone walls (house built in 1900) and a front porch slab slanted toward the house instead of pitched away.
Daryl